The removal of unwanted and/or life threatening biological material from interior portions of bodily cavities, such as organs, vessels, articular joints and structures, sinuses, and various bodily lumens, is a common medical procedure in various medical specialties and disciplines, such as pulmonology, cardiology, urology, gynecology, gastro-enterology, neurology, otolaryngology, orthopedics, and general surgery. Accordingly, various instruments and methods have been employed to perform these procedures.
In one example, the nasal cavity (or nasal fossa) is a large air-filled space above and behind the nose in the middle of the face. The floor of the nasal cavity, which forms the roof of the mouth, is made up by the bones of the hard palate: the horizontal plate of the palatine bone posteriorly and the palatine process of the maxilla anteriorly. To the front of the nasal cavity is the nose, while the back blends, via the choanae, into the nasopharynx.
The paranasal sinuses are hollow cavities in the skull connected by small openings, known as ostia, to the nasal canal. Each ostium between a paranasal sinus and the nasal cavity is formed by bone covered by a layer of mucosal tissue. Normally, air passes into and out of the paranasal sinuses through the ostia and into the nasal canal.
The paranasal sinuses include the maxillary sinuses, the frontal sinuses, the ethmoid sinuses, and the sphenoid sinuses. The maxillary sinuses are also called the maxillary antra and are the largest of the paranasal sinuses. They are located under the eyes, in the maxillary bones. The frontal sinuses are superior to the eyes, in the frontal bone, which forms the hard part of the forehead. The ethmoid sinuses are formed from several discrete air cells within the ethmoid bone between the nose and the eyes. The sphenoid sinuses are in the sphenoid bone at the center of the skull base under the pituitary gland. Sinusitis is an inflammation of the sinus lining commonly caused by bacterial, viral and/or microbial infections; as well as, structural issues such as ostial blockage. Symptoms include nasal congestion, facial discomfort, nasal discharge, headache, and fatigue.
37 million people suffer from chronic sinusitis in the US alone. Initial medical therapy, amounting to $8 B per year, consists of antibiotics, decongestants, and steroids. 25% of patients do not respond to medical therapy. Functional Endoscopic Sinus Surgery (FESS) utilizes debriding equipment to enlarge sinus ostia to encourage drainage. 330,000 FESS are performed/year with an 80% success rate at 3 years. However, complications include CSF leaks, blindness, synechieae, alteration in bone growth, bleeding and infection. FESS is not 100% effective and has a known revision rate of 10%.
More recently, the use of balloon catheters in sinus surgery have been used as described in U.S. Pat. No. 7,854,744 to Becker. In at least some procedures where it is desired to position a balloon catheter in the ostium, it is necessary to advance the catheter through complicated or tortuous anatomy in order to properly position the balloon within the desired sinus ostium. Also, there is a degree of variation in the intranasal and paranasal anatomy of human beings, thus making it difficult to use the stiff-shaft preshaped balloon catheters of Becker for use in all individuals. The Becker patent describes the necessity of having available a set of balloon catheters, each having a particular fixed angle so that the physician can select the appropriate catheter for the patient's anatomy.
A series of U.S. patents to Chang et al. (e.g. U.S. Pat. No. 7,727,226) disclose methods utilizing flexible balloon catheter devices for use in ENT procedures. A sizing balloon situated around the dilating balloon may be inflated using an inflating medium, such as saline with radio-opaque contrast agent or carbon dioxide gas. The distal region of the sizing balloon is supposed to enable the operator to estimate the size of the anatomical opening or the diameter of the narrowest region in a tubular anatomical region.
A common but often undesirable effect resulting from the above described methods and apparatus, is the possibility of the inflation of the balloon portion of the catheter causing sinus ostial fracture, which is sometimes an intended part of the procedure.
Hence, there is a significant need for systems and methods for deforming a body cavity, which in one example, may comprise the sinus ostia, that will not suffer from the drawbacks described herein while still being relatively simple to use and accommodates a single-use strategy.
While the sinus ostia has been described herein, the over inflation of balloon type catheters used in connection with numerous different types of medical procedures and the associated possible breaking or tearing of the cavity due to the inflation is a significant problem.